Messages in this thread | | | Date | Tue, 21 Jun 2011 21:54:21 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [RFC -tip] perf, x86: Add PERF_COUNT_HW_NMI_WATCHDOG event v2 |
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On Tue, Jun 21, 2011 at 07:26:16PM +0200, Stephane Eranian wrote: ... > > > > It doesn't change things much. Of course I can put some specifics into > > .config but where is the guarantee some new generic event would not ever > > intersect with it. I know (for example) we could reserve -1ULL for this > > event but again where is the guarantee that it will never ever be used > > system wide in future for some different event? > > > I am not talking about a new generic PMU event. I am talking about > you hardcoding a raw event in the callback: type = PERF_TYPE_RAW, > config=0x003c. >
watchdog.c is system-wide and even if it's not used by archs other than x86 doesn't mean it'll not in future ;) So we could encode this watchdog event as you mention (and I would check for this values and map it internally to bits I need, this btw will require me to check if this bits do not intersect with some already valid bits combination but it's a different problem) but than we _must_ be sure it never bring problems as new arch or consumer appear. So, no, I don't like this approach, it's fragile. But gimme some time -- I'll re-check all bits, probably there is some workaround.
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